$number_of_results = 5;
$pl = new PageList();
$pl->filterBySomething('blah');
 
// So we get the total returned and base off that
$total = $pl->getTotal() - 1;
$count = 0;
// This is our hand made "page list"
$pages = array();
// This is just to make sure we stay unique
$selected_indexes = array();
 
// Loopin - the $count <= $total is to make sure we
// Don't loop forever if there are less returned
// then number of results we want
while($count <= $total && count($pages) <= $number_of_results) {
  $index = rand(0, $total);
  if(!in_array($index, $selected_indexes) {
    $selected_indexes[] = $index;
    $pages[] = $page_list->get(1, $index);
  }
  $count++;
}
// do something with $pages just like you would have a returned array of pages.